Phase difference resolver of estimated real-time output

Abstract

A phase difference type resolver is adapted such that a calculator calculates an angle from a phase difference at a detection-signal zero cross point, determines a velocity at the angle based on an angle calculated from a phase difference at a previous detection-signal zero cross point, calculates an estimated angle at a next detection-signal zero cross point based on the velocity, divides a difference between the estimated angle and the angle into predetermined minimum detection angles, and outputs a real-time signal based on the minimum detection angles in a range after the angle but before the estimated angle.

1. A phase difference resolver comprising:
 an excitation coil for receiving an excitation signal, 
 a detection coil for outputting a detection signal, and 
 a control unit for outputting an estimated real-time angular signal based on a phase difference between an excitation-signal zero cross point of the excitation signal and a detection-signal zero cross point of the detection signal, 
 wherein the control unit is configured to detect angles at each detection-signal zero cross point from the phase difference between the detection signal and the excitation signal, estimate a velocity at an angle at a detection-signal zero cross point based on the angle and an angle at a previous detection-signal zero cross point, calculate an estimated angle at a next detection-signal zero cross point based on the velocity, divide a difference between the estimated angle and the angle by predetermined minimum detection angles, and output the estimated real-time angular signal changing by the minimum detection angles in a range after the angle but before the estimated angle. 
 
     
     
       2. The phase difference resolver according to  claim 1 , wherein
 the control unit is configured to output the estimated real-time angular signal every time a predetermined time elapses. 
 
     
     
       3. The phase difference resolver according to  claim 2 , wherein
 the estimated real-time angular signal represents an angle obtained by adding or subtracting the minimum detection angle to or from the angle. 
 
     
     
       4. The phase difference resolver according to  claim 1 , wherein
 the control unit is configured to calculate an estimated angle every time an arbitrary time elapses and outputs as the estimated real-time angular signal at that timing. 
 
     
     
       5. The phase difference resolver according to  claim 1 , wherein
 the control unit is configured to estimate the velocity by estimating velocities at a plurality of previous zero cross points, calculating an average of the velocities, and setting the average at the velocity. 
 
     
     
       6. The phase difference resolver according to  claim 5 , wherein
 the control unit is configured to estimate the velocity using the velocities at immediate four or eight previous zero cross points. 
 
     
     
       7. The phase difference resolver according to  claim 1 , wherein
 when an error is present between the estimated angle and an angle at a next excitation-signal zero cross point, the control unit is configured to calculate the velocity at the next excitation-signal zero cross point by correcting the velocity based on the error. 
 
     
     
       8. The phase difference resolver according to  claim 1 , wherein
 the control unit is configured to output the estimated real-time angular signal changing with an interval which is an integral multiple of a basic clock of the control unit. 
 
     
     
       9. The phase difference resolver according to  claim 8 , wherein
 the control unit is configured to extend the interval in which the minimum detection angle is added by one period of the basic clock, by the number of times corresponding to a value obtained by dividing the error by the basic clock. 
 
     
     
       10. The phase difference resolver according to  claim 8 , wherein
 the control unit is configured to output a plurality of pulse trains to output a predetermined time. 
 
     
     
       11. The phase difference resolver according to  claim 1 , wherein
 when a difference between the estimated angle and an angle calculated from a phase difference at the excitation-signal zero cross point is a predetermined value or less, the control unit is configured to perform no calculation on a current angle. 
 
     
     
       12. A phase difference resolver comprising: an excitation coil for receiving an excitation signal, a detection coil for outputting a detection signal, and a control unit for calculating a current angle based on a phase difference between an excitation-signal zero cross point of the excitation coil and a detection-signal zero cross point of the detection signal,
 wherein the control unit is configured to calculate an excitation signal angle from a value of the excitation signal at time, calculate a detection signal angle from a value of the detection signal at the time, and calculate the current angle based on a difference between the excitation signal angle and the detection signal angle.